CA1114625A - Means for increasing the efficiency of an ice disaggregation system - Google Patents
Means for increasing the efficiency of an ice disaggregation systemInfo
- Publication number
- CA1114625A CA1114625A CA334,695A CA334695A CA1114625A CA 1114625 A CA1114625 A CA 1114625A CA 334695 A CA334695 A CA 334695A CA 1114625 A CA1114625 A CA 1114625A
- Authority
- CA
- Canada
- Prior art keywords
- ice
- drum
- teeth
- tooth
- bracket
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
- B63B35/08—Ice-breakers or other vessels or floating structures for operation in ice-infested waters; Ice-breakers, or other vessels or floating structures having equipment specially adapted therefor
- B63B35/12—Ice-breakers or other vessels or floating structures for operation in ice-infested waters; Ice-breakers, or other vessels or floating structures having equipment specially adapted therefor having ice-cutters
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63H—MARINE PROPULSION OR STEERING
- B63H25/00—Steering; Slowing-down otherwise than by use of propulsive elements; Dynamic anchoring, i.e. positioning vessels by means of main or auxiliary propulsive elements
- B63H25/42—Steering or dynamic anchoring by propulsive elements; Steering or dynamic anchoring by propellers used therefor only; Steering or dynamic anchoring by rudders carrying propellers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B1/00—Hydrodynamic or hydrostatic features of hulls or of hydrofoils
- B63B1/02—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement
- B63B1/04—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull
- B63B2001/044—Hydrodynamic or hydrostatic features of hulls or of hydrofoils deriving lift mainly from water displacement with single hull with a small waterline area compared to total displacement, e.g. of semi-submersible type
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B2211/00—Applications
- B63B2211/06—Operation in ice-infested waters
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In an ice disaggregation system employing teeth affixed to a bracket which is spirally disposed around the outer periphery of a cylindrical rotating drum and held in spaced relationship therefrom, the cutting cap-acity is improved by tilting the plane of each tooth with respect to the drum's axis of rotation such that each incremental section of ice which a tooth engages is subjected to a bending force about a pivot near an area from which ice has been removed is therefore rela-tively weak. As a result, the ice readily fractures in relatively large chunks.
In an ice disaggregation system employing teeth affixed to a bracket which is spirally disposed around the outer periphery of a cylindrical rotating drum and held in spaced relationship therefrom, the cutting cap-acity is improved by tilting the plane of each tooth with respect to the drum's axis of rotation such that each incremental section of ice which a tooth engages is subjected to a bending force about a pivot near an area from which ice has been removed is therefore rela-tively weak. As a result, the ice readily fractures in relatively large chunks.
Description
~4ÇiZ~
- .
BACKGROUND OF_THE INVENTION
This invention relates to the ice disaggregating arts and, more particularly, to aspects of the ice engaging teeth and of the means by which supported upon a large, vertically oriented drum adapted to engage and disaggregate ice.
In the petroleum exploration and production industry, `;
it is o~ten necessary to move and station men and equipment in relatively hostile environmental regions. In recent years, the emphasis on oil production from the far north has necessitated the development of new techniques for en-countering ~ormations of encroaching ice floes and the move-ments thereof which threaten the stability and/or position of equipment situated therearound.
In the Arctic, large offshore regions are often cover-ed by thick layers o~ ice. Currently, there is considerable activity in this and other frozen areas directed toward the dlscovery and development of sources of petroleum and other natural resources. The search for and production of these resources require operational platforms for housing equip-ment and personnel. These plat~orms are manually transpor-ted to their operational sites and are maintained in a rel-atively fixed position with respect to the underwater floor by anchoring thereto and/or the utilization o~ dynamic pos-itioning techniques. It may be noted, however, that some such plat~orms are s01f-propelled. In the normal course of operation, pipes are extended from the platform into the earth's sub-surface for the recovery of natural resources ~4~2~
such as petroleum. It is thus important to maintain the platform within a predetermined envelope in order to pre-vent breaking or withdrawing the pipe from the earth.
Platforms located in both shallow and deep covered waters are exposed to ice floes which sometimes float free-ly on the water and/or a unitary ice mass which flow in-sidiously. The ice may be comprised of such mass that a platform is susceptible to damage or destruction as a re-sult of forces imparted thereafainst by the moving ice.
The Arctic Ocean, for example, is characterized by air temperatures ranging from -70F to 70F, ice sheets and thicknesses between 6 and 10 feet, and pressure ridges of 10 to 100 feet. In such conditions, ice typically exhibits a compressive strength of 1,000-3,000 psi and tensile strength of 300-1,000 psi. The problems of providing the requisite magnitude o~ ~orce and power necessary for engagement with and disaggregation o~ such an environmental threat may be seen to be formidable.
Drilling and operations platforms for use in ice cov-ered areas may take several different i'orms. One such plat-form includes a monopod, semi-submersible design utilizing a single rotating cutter completely encircling the inter-mediate hull section proximate the waterline for ice floe enKagement and disaggregation. The cutter is disposed be-tween upper superstructure comprising an operations platform and a submerged hull providing flotation. In this manner, only a relatively narrow profile emerges through encroach-ing ice layers while plati'orm surface area is maximized and . !
buoyancy size parameters are met, respectively, above and below the ice.
A similar operations plat~orm, which is disclosed in ;
detail in United States Patent application Serial Number 772,784, filed February 28, 1977, and entitled "Operations Vessel for Ice Covered Seas", now U.S. Patent 4,102,288, includes a monopod, semi-submersible drilling vessel con-structed with an ice breaking bow and aft ice disaggrega-tion apparatus comprising an intermediate hull section.
The bow is constructed in the iorm o~ a nautical wedge for iacilitating transit operation in both open and ice laden waters and for breaking ice within its capability while in the operating mode. In addition, the intermediate hull section also includes a plurality of drums rotatably mounted in generally upstanding relationship relative to the sub-mersible hull. The drums are comprised o~ an outer surface adapted ior breaking, cutting and/or chipping ice engaged thereby. Typically, a pair of drums is mounted for counter-rotation such that reaction torque is cancelled.
A floating platform which employs somewhat similar ice engaging and disaggregating means is disclosed in United States Patent 4,070,052 entitled "Method and Apparatus for Disaggregating Particulate Matter". The plati'orm disclosed therein includes ice disaggregating apparatus supported by booms which include telescoping struts which support the ice disaggregation apparatus i'or movement around the entire platform. More particularly, an array of rotatable cutting drums is configured with the axis of rotation of one drum ~orming an oblique angle with the axis of rotation of a r . . , ~
4~
second drum. Rotation o~ the drums produces improved mass removal e~ectiveness by first cutting and chipping serra-tions to ~orm ridges therebetween which subsequently shatter when struck at an oblique angle by the cutters of a second drum. In a variance con~iguration, an array of three, in-dependently rotatable drums mounted in a triangular config-uration is employed, Each drum is comprised of a generally elliptical cross-sectional shape wherein teeth protruding outwardly o~ adjacent drums do not overlap.
Yet another ice disaggregating system o~ interest as prior art to the present invention is disclosed in U.S.
Patent 4,069,783 entitled "Method and Apparatus for Disag-gregating Particulate ~atter". As disclosed and discussed in detail therein, the ice disaggregation system comprises the employment o~ a vertically oriented, rotatable drum disposed ahead o~, and adapted to sweep across the path o~, a ship ~rom which the drum is supported. The teeth disposed on the rotatable drum have aligned pairs of sledging teeth or progressively increasing lengths extending therefrom.
~djacent each array o~ aligned pairs o~ sledging teeth, centrally positioned therebetween and to the rotative rear thereo~, there is provided a slugging tooth adapted ~or striking engagement with the particulate matter engaged and laterally isolated therebetween by the sledging teeth.
It is important to appreciate that the teeth carrying, ice engaging drums discussed in the ~oregoing are all very large, particularly those associated with the semi-submersible operations vessels. It has been ~ound that, when such drums become so large, the coniiguration of the ice engaging teeth $2~
and their respective mounting means is of great importance if acceptable efficiency is to be obtained in driving the ice disengaging drums and if acceptable tooth life and maintenance methods are to be obtained. That is, the rel-atively straightforward tooth designs and mounting means characteristic of conventional drum ice disaggregating means (which have been in use for many years) cannot simply be scaled up to obtain the desired quality and economy of operation, ~abrication, and maintenance necessary in such very large installations as herein contemplated.
SU~MARY OF THE INVENTION ~-It is thereiore a broad object of this invention to provide improved ice disaggregation means.
It is another object o~ this invention to provide improved ice engaging teeth especially suited ~or employ-ment with large revolving drums which carry such teeth peripherally disposed ~or engagement with large ice masses.
It is a more particular object oi this invention to provide such teeth by which ice i'racturing is obtained with less expenditure of ~orce needed to propel the teeth.
Brieily, these and other ob~ects o~ the invention are accomplished by employing teeth which are multiple-tined.
In one configuration, each tooth has two equal length, poin-ted tines. In a presently preierred con~iguration, a long pointed central tine is flanked by a pair o~ shorter pointed tines.
DESCRIPTION OF THE DRAWING
The subject matter of the invention is particularly - pointed out and distinctly claimed in the concluding por-tion o~ the specification. The invention, however, both as t~ organization and method of operation may best be understood by re~erence to the following description taken ~ -in conjunction with the accompanying drawing of which:
Figure 1 illustrates a typical environment in which the present invention finds favorable use, which environ-ment comprises a semi-submersible operations platform ~itted with very large ice disaggregating means;
Figure 2 is a view of one of the ice disaggregating drums employed in the operations plati'orm in Figure l;
Figure 3 is a detailed view of one configuration for a bracket/tooth unit as employed on the drum illustrated in Figure 2;
Figure 4 is a view taken along the lines 4-4 of Figure 3;
Figure 5 is a cross-sectional view taken along the lines 5-5 oi Figure 4;
Figure 6 illustrates a variant configuration for a bracket/tooth unit which may be employed on the drum of Figure 2;
Figure 7 is a cross-sectional view taken along the lines 7-7 oi Figure 6;
Figure 8 is a partial view oi' one o~ the teeth illus-trated in Figures 6 and 7 showing certain details of its ' pre~erred construction;
4~3 ~ igure 9 is a cross-sectional view taken along the lines 9-9 of Figure B;
Figure 10 is a fragmentary view illustrating the operation of the bracket/tooth combination illustrated in Figure 6 as it is efiecting ice disaggregation;
Figure 11 is a partial view of a variant, multiple tined tooth which may be employed in eithe~ of the bracket/
tooth units illustrated in Figures 3 and 6; and Figure 12 is a partial view illustrating another var~ant multiple tined tooth which may be employed in the bracket/tooth units illustrated in Figures 3 and 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reierring now to Figure 1, an exemplary environment ~or the present invention is shown and comprises an opera-tions vessel 10 which is a semi-submersible, monopod type plat~orm ~or drilling, production, processing, and/or stor-age and the like. The plat~orm lO is provided with a ~lo-tation hull section 12 adapted ~or submerged support and sustenance o~ the remaining vessel and also providing stor-age there~or. A plurality oi propulsion units 14 are con-structed around the ~lotation hull 12 ~or providing a transit ;`
mode o~ operation, dynamic positioning while in a stationary mode, and the capacity to engage ice iloes in the position-ing and operation thereo~.
The plat~orm 10 is constructed with an intermediate hull section extending upwardly from the flotàtion hull 12 and includes a nautical wedge portion 18 and an ice disag-gregation portion comprising counter-rotating drums 36 and ~3 4~
~:
38. Atop the intermediate hull, a deck structure 22 is con-structed for housing above-water operations. A shrouded derrick 26 upstands from the deck structure 22, the shroud being provided for safety and environmental protection and ~or decreasing wind drag forces. An operation area 30 is similarly provided in a shrouded configuration beneath and adjacent the derrick 26 for protecting platform personnel during plat~orm operations. In the shrouded configuration shown, the topside profile of the platform 10 is substan-tially comprised of circular shapes which eliminate wind direction sensitivity to the vessel.
In Figure 1, the platform 10 is shown advancing in a transit mode through an ice sheet 50. It will be obser-ved that counter-rotating drum cutters 36, 38, disaggregate the ice sheet in order to permit relative movement (indic-ated by the arrow 6~) between the ice sheet 50 and the plat-form 10 in a direction generally governed by the orientation Or the thrusters 14. More detailed description of the opera-tions vessel 10 will be I'ound in the aforementioned U.S.
patent application Serial Number 772,787, now U.S. Pa-tent 4,102,288. As previously indicated, the present invention is directed to improvements in the teeth structure associa-ted with the ice disaggregating drums 36, 38 or similar ice dtsaggregating drums.
It is important, in order to obtain a full understand-in~ o the present invention, that some appreciation of the size o~ the relevant structure be obtained. Thus, referring to Figure 2 which is an isolated view of the disaggregating drum 36, it will be understood that the axial dimension oi the drum 36 is on the order oi' 50 to 100 feet or even more.
As shown in Figure 2, the drum 36 is provided with a plural-ity of axially displaced, circumierentially distributed rows of tooth-carrying brackets la> lb, lc, ld, le; 2a, 2b, 2c, 2d, 2e; 3a, 3b, 3c, 3d, 3e; and 4a, 4c, 4d, 4e. It will be understood, of course, that the bracket rows extend around the complete circum~erence o~ the drum 36. The brackets in ad~acent axially displaced rows are generally arranged in a spiral. Thus, bracket lb leads bracket 2c which leads brac-ket 3d which leads bracket 4e, etc.
As best shown in Figure 3, each bracket, such as the bracket 1, comprises upper and lower standoif portions 5, 6, between the outer ends o~ which extends a tooth-carrying beam portion 7. Upper and lower ioot portions 8, 9, oi the bracket 1 bear against the suri'ace oi' the drum 36 to provide areas oi' attachment thereto ior the bracket 1, With respect to dimensions, the lengths oi the stand-oi'~ portions 5 and 6 oi the bracket 1 are such that the beam portion 7 stands away irom the sur~ace of the drum 36 several ~eet; i.e., on the order oi 2-5 ~eet. The beam por-tion 7 o~ the bracket 1 carries a plurality oi i'orward-facing, ice-engaging teeth 11. Intermediate the length oi the beam portion 7 may be provided one or more support members 13 which extend irom the suriace oi the drum 36 to the under-side of the beam portion 7, thereby imparting additional rigidity thereto. Figures 4 and 5 illustrate one specii'ic con~iguration for the support member 13 and its orientation with respect to the beam portion 7 of the bracket 1.
In operation, as the teeth 11 engage and fracture the ice in chunks, the ice chunks float toward the surface and are discharged to the rear. During their upward transit, the chunks may pass between the surface of the drum and the beam portion 7 of the brackets, sufficient clearance being provided, as pre~iously stated, to obtain that facility.
The teeth 11 depicted in Figures 2-5 are oriented ;~
generally parallel to the axis of the cylinder 36, and efficient ice disaggregation is accomplished with such teeth. However, attention is directed to a more efficient tooth orientation illustrated in Figure 6. A bracket 40, comprising foot portions 41 and 42, standoff portions 43 and 44, and a beam portion 45, supports a plurality of ice-disaggregating teeth 46. As best shown in Figure 7, each tooth 46 includes an intermediate section 47 which is twisted to bring the ice-engaging forward section of the tooth into an angular relationship with respect to the axis o~ the drum 36. The twist is imparted in a direction such that the upper edge of the ice-engaging forward section of ~0 each tooth 36 is radially outwardly disposed with respect to the lower edge. The eifect of this orientation may best be nppreciated with reference to Figure 10 which illustrates an ice chunk 48 whcih has just been separated from the ice sheet 50 by the action of the tooth 46a. The following tooth 46b is fracturing the ice in the region 51, and the stress is in the tension mode, thus tending to lift and pry the ice chunk intermediate the teeth 46a and 46b upwardly and away from the ice sheet 50. It will be appreciated that a much more efficient fracture mode is thereby obtained which :.0 significantly lowers the power required to disaggregate the ice.
1~4Ç~
;.
The pointed configuration of the teeth 46 is prefer-able to the broad chisel edge of the teeth 11 shown in Figure 3. In addition, by raking the ice engaging edge of the teeth 46, as shown in the region 39 of Figure 9, the cutting abilities and the life of a tooth before recondition-ing is necessary is substantially improved. -Because of the need to replace broken teeth, as well as to periodically recondition worn teeth, the individual teeth are preierably individually replaceable. Referring again to Figure 7, a tooth 46 having a twisted portion 47, a tine portion 49 and a base portion 51 is shown affixed to the beam portion 45 of the brac~ed 40. A brace 52 is ~ixed to the inside suriace oi' the beam portion 45 and has a iorward portion which extends toward the suriace of the drum 36 and, in conjunction with a ~orward region oi the beam portion 45, deilnes a recess ior receiving the base portion 51 oi the tooth 46. An aperture 54 through the base portion 51 o~ the tooth 46 is brought into alignment with corresponding apertures 53 and 55 in the beam portion 45 and the brace 52, respectively, in order that nut and bolt means 56 may be employed to secure the tooth 46 to the bracket 40. The brace 52 is preierably permanently welded to the inside oi the beam portion 45 whereas any convenient menns alternative to the nut and bolt 56 may be utilized to removably iix the tooth 46 in place. The dimensions in Fig-ure 7 are somewhat distorted to permit a clear illustration of the subject matter explained therein. In particular, as previously noted, the height o~ the stand oii portion 43 of the bracket 40 is several ieet and is thus shown substantially 3() undersized in Figure 7.
~ ~4~Z~ ~ :
.
In addition to the single tined tooth configuration ~-illustrated in Figures 6-9 and the chisel configuration : .
shown in Figures 3 and 4, it has been found that multiple tine tooth configurations as illustrated in Figures 11 and 12 afford further increases in the efficiency of ice dis-aggregation by the system. As shown in Figure 11, a plur-ality (two, as shown) of identical spaced apart tines 57, 58 are employed on the alternate embodiment tooth 59 illus-trated. Figure 12 presents a still more efficient tooth con~iguration which utilizes a central, relatively long tine 60 flanked by shorter tines ~1 and 62 for the tooth 63 As indicated by the dashed lines 65 and 66, respec-tively, one face of each of the teeth 59 and 63 has an undercut leading edge corresponding to the region 39 of the tooth 46 illustrated in Figure 9. The same benefits accrue therefrom to the alternate configured teeth 59 and ~3.
While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifi-cations o~ structure, arrangments, proportions, the elements, materials, and components, used in the practice of the in-vcntion which are particularly adapted for specific environ-ments and operating requirements without departing from those principles.
- .
BACKGROUND OF_THE INVENTION
This invention relates to the ice disaggregating arts and, more particularly, to aspects of the ice engaging teeth and of the means by which supported upon a large, vertically oriented drum adapted to engage and disaggregate ice.
In the petroleum exploration and production industry, `;
it is o~ten necessary to move and station men and equipment in relatively hostile environmental regions. In recent years, the emphasis on oil production from the far north has necessitated the development of new techniques for en-countering ~ormations of encroaching ice floes and the move-ments thereof which threaten the stability and/or position of equipment situated therearound.
In the Arctic, large offshore regions are often cover-ed by thick layers o~ ice. Currently, there is considerable activity in this and other frozen areas directed toward the dlscovery and development of sources of petroleum and other natural resources. The search for and production of these resources require operational platforms for housing equip-ment and personnel. These plat~orms are manually transpor-ted to their operational sites and are maintained in a rel-atively fixed position with respect to the underwater floor by anchoring thereto and/or the utilization o~ dynamic pos-itioning techniques. It may be noted, however, that some such plat~orms are s01f-propelled. In the normal course of operation, pipes are extended from the platform into the earth's sub-surface for the recovery of natural resources ~4~2~
such as petroleum. It is thus important to maintain the platform within a predetermined envelope in order to pre-vent breaking or withdrawing the pipe from the earth.
Platforms located in both shallow and deep covered waters are exposed to ice floes which sometimes float free-ly on the water and/or a unitary ice mass which flow in-sidiously. The ice may be comprised of such mass that a platform is susceptible to damage or destruction as a re-sult of forces imparted thereafainst by the moving ice.
The Arctic Ocean, for example, is characterized by air temperatures ranging from -70F to 70F, ice sheets and thicknesses between 6 and 10 feet, and pressure ridges of 10 to 100 feet. In such conditions, ice typically exhibits a compressive strength of 1,000-3,000 psi and tensile strength of 300-1,000 psi. The problems of providing the requisite magnitude o~ ~orce and power necessary for engagement with and disaggregation o~ such an environmental threat may be seen to be formidable.
Drilling and operations platforms for use in ice cov-ered areas may take several different i'orms. One such plat-form includes a monopod, semi-submersible design utilizing a single rotating cutter completely encircling the inter-mediate hull section proximate the waterline for ice floe enKagement and disaggregation. The cutter is disposed be-tween upper superstructure comprising an operations platform and a submerged hull providing flotation. In this manner, only a relatively narrow profile emerges through encroach-ing ice layers while plati'orm surface area is maximized and . !
buoyancy size parameters are met, respectively, above and below the ice.
A similar operations plat~orm, which is disclosed in ;
detail in United States Patent application Serial Number 772,784, filed February 28, 1977, and entitled "Operations Vessel for Ice Covered Seas", now U.S. Patent 4,102,288, includes a monopod, semi-submersible drilling vessel con-structed with an ice breaking bow and aft ice disaggrega-tion apparatus comprising an intermediate hull section.
The bow is constructed in the iorm o~ a nautical wedge for iacilitating transit operation in both open and ice laden waters and for breaking ice within its capability while in the operating mode. In addition, the intermediate hull section also includes a plurality of drums rotatably mounted in generally upstanding relationship relative to the sub-mersible hull. The drums are comprised o~ an outer surface adapted ior breaking, cutting and/or chipping ice engaged thereby. Typically, a pair of drums is mounted for counter-rotation such that reaction torque is cancelled.
A floating platform which employs somewhat similar ice engaging and disaggregating means is disclosed in United States Patent 4,070,052 entitled "Method and Apparatus for Disaggregating Particulate Matter". The plati'orm disclosed therein includes ice disaggregating apparatus supported by booms which include telescoping struts which support the ice disaggregation apparatus i'or movement around the entire platform. More particularly, an array of rotatable cutting drums is configured with the axis of rotation of one drum ~orming an oblique angle with the axis of rotation of a r . . , ~
4~
second drum. Rotation o~ the drums produces improved mass removal e~ectiveness by first cutting and chipping serra-tions to ~orm ridges therebetween which subsequently shatter when struck at an oblique angle by the cutters of a second drum. In a variance con~iguration, an array of three, in-dependently rotatable drums mounted in a triangular config-uration is employed, Each drum is comprised of a generally elliptical cross-sectional shape wherein teeth protruding outwardly o~ adjacent drums do not overlap.
Yet another ice disaggregating system o~ interest as prior art to the present invention is disclosed in U.S.
Patent 4,069,783 entitled "Method and Apparatus for Disag-gregating Particulate ~atter". As disclosed and discussed in detail therein, the ice disaggregation system comprises the employment o~ a vertically oriented, rotatable drum disposed ahead o~, and adapted to sweep across the path o~, a ship ~rom which the drum is supported. The teeth disposed on the rotatable drum have aligned pairs of sledging teeth or progressively increasing lengths extending therefrom.
~djacent each array o~ aligned pairs o~ sledging teeth, centrally positioned therebetween and to the rotative rear thereo~, there is provided a slugging tooth adapted ~or striking engagement with the particulate matter engaged and laterally isolated therebetween by the sledging teeth.
It is important to appreciate that the teeth carrying, ice engaging drums discussed in the ~oregoing are all very large, particularly those associated with the semi-submersible operations vessels. It has been ~ound that, when such drums become so large, the coniiguration of the ice engaging teeth $2~
and their respective mounting means is of great importance if acceptable efficiency is to be obtained in driving the ice disengaging drums and if acceptable tooth life and maintenance methods are to be obtained. That is, the rel-atively straightforward tooth designs and mounting means characteristic of conventional drum ice disaggregating means (which have been in use for many years) cannot simply be scaled up to obtain the desired quality and economy of operation, ~abrication, and maintenance necessary in such very large installations as herein contemplated.
SU~MARY OF THE INVENTION ~-It is thereiore a broad object of this invention to provide improved ice disaggregation means.
It is another object o~ this invention to provide improved ice engaging teeth especially suited ~or employ-ment with large revolving drums which carry such teeth peripherally disposed ~or engagement with large ice masses.
It is a more particular object oi this invention to provide such teeth by which ice i'racturing is obtained with less expenditure of ~orce needed to propel the teeth.
Brieily, these and other ob~ects o~ the invention are accomplished by employing teeth which are multiple-tined.
In one configuration, each tooth has two equal length, poin-ted tines. In a presently preierred con~iguration, a long pointed central tine is flanked by a pair o~ shorter pointed tines.
DESCRIPTION OF THE DRAWING
The subject matter of the invention is particularly - pointed out and distinctly claimed in the concluding por-tion o~ the specification. The invention, however, both as t~ organization and method of operation may best be understood by re~erence to the following description taken ~ -in conjunction with the accompanying drawing of which:
Figure 1 illustrates a typical environment in which the present invention finds favorable use, which environ-ment comprises a semi-submersible operations platform ~itted with very large ice disaggregating means;
Figure 2 is a view of one of the ice disaggregating drums employed in the operations plati'orm in Figure l;
Figure 3 is a detailed view of one configuration for a bracket/tooth unit as employed on the drum illustrated in Figure 2;
Figure 4 is a view taken along the lines 4-4 of Figure 3;
Figure 5 is a cross-sectional view taken along the lines 5-5 oi Figure 4;
Figure 6 illustrates a variant configuration for a bracket/tooth unit which may be employed on the drum of Figure 2;
Figure 7 is a cross-sectional view taken along the lines 7-7 oi Figure 6;
Figure 8 is a partial view oi' one o~ the teeth illus-trated in Figures 6 and 7 showing certain details of its ' pre~erred construction;
4~3 ~ igure 9 is a cross-sectional view taken along the lines 9-9 of Figure B;
Figure 10 is a fragmentary view illustrating the operation of the bracket/tooth combination illustrated in Figure 6 as it is efiecting ice disaggregation;
Figure 11 is a partial view of a variant, multiple tined tooth which may be employed in eithe~ of the bracket/
tooth units illustrated in Figures 3 and 6; and Figure 12 is a partial view illustrating another var~ant multiple tined tooth which may be employed in the bracket/tooth units illustrated in Figures 3 and 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reierring now to Figure 1, an exemplary environment ~or the present invention is shown and comprises an opera-tions vessel 10 which is a semi-submersible, monopod type plat~orm ~or drilling, production, processing, and/or stor-age and the like. The plat~orm lO is provided with a ~lo-tation hull section 12 adapted ~or submerged support and sustenance o~ the remaining vessel and also providing stor-age there~or. A plurality oi propulsion units 14 are con-structed around the ~lotation hull 12 ~or providing a transit ;`
mode o~ operation, dynamic positioning while in a stationary mode, and the capacity to engage ice iloes in the position-ing and operation thereo~.
The plat~orm 10 is constructed with an intermediate hull section extending upwardly from the flotàtion hull 12 and includes a nautical wedge portion 18 and an ice disag-gregation portion comprising counter-rotating drums 36 and ~3 4~
~:
38. Atop the intermediate hull, a deck structure 22 is con-structed for housing above-water operations. A shrouded derrick 26 upstands from the deck structure 22, the shroud being provided for safety and environmental protection and ~or decreasing wind drag forces. An operation area 30 is similarly provided in a shrouded configuration beneath and adjacent the derrick 26 for protecting platform personnel during plat~orm operations. In the shrouded configuration shown, the topside profile of the platform 10 is substan-tially comprised of circular shapes which eliminate wind direction sensitivity to the vessel.
In Figure 1, the platform 10 is shown advancing in a transit mode through an ice sheet 50. It will be obser-ved that counter-rotating drum cutters 36, 38, disaggregate the ice sheet in order to permit relative movement (indic-ated by the arrow 6~) between the ice sheet 50 and the plat-form 10 in a direction generally governed by the orientation Or the thrusters 14. More detailed description of the opera-tions vessel 10 will be I'ound in the aforementioned U.S.
patent application Serial Number 772,787, now U.S. Pa-tent 4,102,288. As previously indicated, the present invention is directed to improvements in the teeth structure associa-ted with the ice disaggregating drums 36, 38 or similar ice dtsaggregating drums.
It is important, in order to obtain a full understand-in~ o the present invention, that some appreciation of the size o~ the relevant structure be obtained. Thus, referring to Figure 2 which is an isolated view of the disaggregating drum 36, it will be understood that the axial dimension oi the drum 36 is on the order oi' 50 to 100 feet or even more.
As shown in Figure 2, the drum 36 is provided with a plural-ity of axially displaced, circumierentially distributed rows of tooth-carrying brackets la> lb, lc, ld, le; 2a, 2b, 2c, 2d, 2e; 3a, 3b, 3c, 3d, 3e; and 4a, 4c, 4d, 4e. It will be understood, of course, that the bracket rows extend around the complete circum~erence o~ the drum 36. The brackets in ad~acent axially displaced rows are generally arranged in a spiral. Thus, bracket lb leads bracket 2c which leads brac-ket 3d which leads bracket 4e, etc.
As best shown in Figure 3, each bracket, such as the bracket 1, comprises upper and lower standoif portions 5, 6, between the outer ends o~ which extends a tooth-carrying beam portion 7. Upper and lower ioot portions 8, 9, oi the bracket 1 bear against the suri'ace oi' the drum 36 to provide areas oi' attachment thereto ior the bracket 1, With respect to dimensions, the lengths oi the stand-oi'~ portions 5 and 6 oi the bracket 1 are such that the beam portion 7 stands away irom the sur~ace of the drum 36 several ~eet; i.e., on the order oi 2-5 ~eet. The beam por-tion 7 o~ the bracket 1 carries a plurality oi i'orward-facing, ice-engaging teeth 11. Intermediate the length oi the beam portion 7 may be provided one or more support members 13 which extend irom the suriace oi the drum 36 to the under-side of the beam portion 7, thereby imparting additional rigidity thereto. Figures 4 and 5 illustrate one specii'ic con~iguration for the support member 13 and its orientation with respect to the beam portion 7 of the bracket 1.
In operation, as the teeth 11 engage and fracture the ice in chunks, the ice chunks float toward the surface and are discharged to the rear. During their upward transit, the chunks may pass between the surface of the drum and the beam portion 7 of the brackets, sufficient clearance being provided, as pre~iously stated, to obtain that facility.
The teeth 11 depicted in Figures 2-5 are oriented ;~
generally parallel to the axis of the cylinder 36, and efficient ice disaggregation is accomplished with such teeth. However, attention is directed to a more efficient tooth orientation illustrated in Figure 6. A bracket 40, comprising foot portions 41 and 42, standoff portions 43 and 44, and a beam portion 45, supports a plurality of ice-disaggregating teeth 46. As best shown in Figure 7, each tooth 46 includes an intermediate section 47 which is twisted to bring the ice-engaging forward section of the tooth into an angular relationship with respect to the axis o~ the drum 36. The twist is imparted in a direction such that the upper edge of the ice-engaging forward section of ~0 each tooth 36 is radially outwardly disposed with respect to the lower edge. The eifect of this orientation may best be nppreciated with reference to Figure 10 which illustrates an ice chunk 48 whcih has just been separated from the ice sheet 50 by the action of the tooth 46a. The following tooth 46b is fracturing the ice in the region 51, and the stress is in the tension mode, thus tending to lift and pry the ice chunk intermediate the teeth 46a and 46b upwardly and away from the ice sheet 50. It will be appreciated that a much more efficient fracture mode is thereby obtained which :.0 significantly lowers the power required to disaggregate the ice.
1~4Ç~
;.
The pointed configuration of the teeth 46 is prefer-able to the broad chisel edge of the teeth 11 shown in Figure 3. In addition, by raking the ice engaging edge of the teeth 46, as shown in the region 39 of Figure 9, the cutting abilities and the life of a tooth before recondition-ing is necessary is substantially improved. -Because of the need to replace broken teeth, as well as to periodically recondition worn teeth, the individual teeth are preierably individually replaceable. Referring again to Figure 7, a tooth 46 having a twisted portion 47, a tine portion 49 and a base portion 51 is shown affixed to the beam portion 45 of the brac~ed 40. A brace 52 is ~ixed to the inside suriace oi' the beam portion 45 and has a iorward portion which extends toward the suriace of the drum 36 and, in conjunction with a ~orward region oi the beam portion 45, deilnes a recess ior receiving the base portion 51 oi the tooth 46. An aperture 54 through the base portion 51 o~ the tooth 46 is brought into alignment with corresponding apertures 53 and 55 in the beam portion 45 and the brace 52, respectively, in order that nut and bolt means 56 may be employed to secure the tooth 46 to the bracket 40. The brace 52 is preierably permanently welded to the inside oi the beam portion 45 whereas any convenient menns alternative to the nut and bolt 56 may be utilized to removably iix the tooth 46 in place. The dimensions in Fig-ure 7 are somewhat distorted to permit a clear illustration of the subject matter explained therein. In particular, as previously noted, the height o~ the stand oii portion 43 of the bracket 40 is several ieet and is thus shown substantially 3() undersized in Figure 7.
~ ~4~Z~ ~ :
.
In addition to the single tined tooth configuration ~-illustrated in Figures 6-9 and the chisel configuration : .
shown in Figures 3 and 4, it has been found that multiple tine tooth configurations as illustrated in Figures 11 and 12 afford further increases in the efficiency of ice dis-aggregation by the system. As shown in Figure 11, a plur-ality (two, as shown) of identical spaced apart tines 57, 58 are employed on the alternate embodiment tooth 59 illus-trated. Figure 12 presents a still more efficient tooth con~iguration which utilizes a central, relatively long tine 60 flanked by shorter tines ~1 and 62 for the tooth 63 As indicated by the dashed lines 65 and 66, respec-tively, one face of each of the teeth 59 and 63 has an undercut leading edge corresponding to the region 39 of the tooth 46 illustrated in Figure 9. The same benefits accrue therefrom to the alternate configured teeth 59 and ~3.
While the principles of the invention have now been made clear in an illustrative embodiment, there will be immediately obvious to those skilled in the art many modifi-cations o~ structure, arrangments, proportions, the elements, materials, and components, used in the practice of the in-vcntion which are particularly adapted for specific environ-ments and operating requirements without departing from those principles.
Claims (3)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED
AS FOLLOWS:
1. In an ice desegregation system characterized by at least one rotating drum, which drum carries ice engaging teeth structure on the peripheral surface thereof, the im-provement comprising:
A) a plurality of tooth supporting brackets distrib-uted about and affixed to the peripheral surface of the drum, each of said brackets including an elonga-ted tooth carrying beam portion disposed generally parallel to the drum peripheral surface and rigidly supported outwardly therefrom by a plurality of bracket legs;
B) a plurality of ice engaging teeth fixed to said bracket beam portion, each of said teeth having a sharp, ice engaging forward portion, said teeth be-ing oriented such that the forward portions thereof generally face the direction of drum rotation; and C) each of said teeth being further oriented such that said forward portion is disposed at an acute angle with respect to the drum axis, the upper edge of said forward portion extending radially outward-ly further from the drum surface than the lower edge thereof.
A) a plurality of tooth supporting brackets distrib-uted about and affixed to the peripheral surface of the drum, each of said brackets including an elonga-ted tooth carrying beam portion disposed generally parallel to the drum peripheral surface and rigidly supported outwardly therefrom by a plurality of bracket legs;
B) a plurality of ice engaging teeth fixed to said bracket beam portion, each of said teeth having a sharp, ice engaging forward portion, said teeth be-ing oriented such that the forward portions thereof generally face the direction of drum rotation; and C) each of said teeth being further oriented such that said forward portion is disposed at an acute angle with respect to the drum axis, the upper edge of said forward portion extending radially outward-ly further from the drum surface than the lower edge thereof.
2. The system of Claim 1 in which each of said teeth is individually removably affixed to its corresponding brack-et.
3. The system of Claim 2 which further includes a brace member having a rearward portion affixed to the sur-face of said bracket which faces the surface of said drum, said brace member having a forward portion spaced from said bracket and defining a recess therewith, each of said teeth further having a rearward portion, said recess being adap-ted to receive and brace said tooth rearward portion, and means for removably securing each said tooth rearward por-tion in said recess.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US940,245 | 1978-09-07 | ||
| US05/940,245 US4422399A (en) | 1978-09-07 | 1978-09-07 | Means for increasing the efficiency of an ice disaggregation system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114625A true CA1114625A (en) | 1981-12-22 |
Family
ID=25474480
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA334,695A Expired CA1114625A (en) | 1978-09-07 | 1979-08-29 | Means for increasing the efficiency of an ice disaggregation system |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4422399A (en) |
| CA (1) | CA1114625A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4547093A (en) * | 1982-08-10 | 1985-10-15 | Statham John A | Protection of vessels and equipment from moving ice |
| US7180981B2 (en) | 2002-04-08 | 2007-02-20 | Nanodynamics-88, Inc. | High quantum energy efficiency X-ray tube and targets |
| KR101636046B1 (en) * | 2014-06-26 | 2016-07-05 | 삼성중공업 주식회사 | Floating type ice-breaking apparatus |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US936793A (en) * | 1908-12-22 | 1909-10-12 | Charles R Middleton | Cutting-tool for planers, lathes, &c. |
| US1258109A (en) * | 1913-07-15 | 1918-03-05 | Firm Of Heinrich Lanz | Cultivator. |
| US2346317A (en) * | 1942-08-31 | 1944-04-11 | Int Harvester Co | Stalk cutter |
| US2665655A (en) * | 1950-07-12 | 1954-01-12 | George R Brown | Machine for disintegrating and removing ice to form navigation channels |
| US2856708A (en) * | 1955-01-03 | 1958-10-21 | George R Schnore | Attachment for bulldozer blades |
| US3303588A (en) * | 1963-09-25 | 1967-02-14 | Wausau Iron Works | Rotary snow plow |
| US3768428A (en) * | 1971-11-24 | 1973-10-30 | Air Logistics Corp | Sweep ice cutter |
| US4005666A (en) * | 1974-04-08 | 1977-02-01 | Sea-Log Corporation | Fluid vacuum release for ice cutting systems |
| US4070062A (en) * | 1976-11-11 | 1978-01-24 | Sun Oil Company Limited | Method of and apparatus for disaggregating particulate matter |
-
1978
- 1978-09-07 US US05/940,245 patent/US4422399A/en not_active Expired - Lifetime
-
1979
- 1979-08-29 CA CA334,695A patent/CA1114625A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4422399A (en) | 1983-12-27 |
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